I was driving along a dual carriageway that was merging from the outside (right) lane into one (left) lane. I was in the left hand lane in a line of traffic, when a car on the outside of me trying to merge hit me on my driver side rear passenger door and my rear wing. I put a claim in to my insurance company but they are now saying it was 50-50. I explained that the other vehicle had driven into my car as evidence of the damage sustained shows that my rear had been damaged, whereas if I had driven into their car my front would have sustained damage not the rear. Is it incumbent on the driver who is intent on performing a change of lane, to ensure there is sufficient room for their manoeuvre? The Highway Code does not mention anything with regard to this.